Gyriform infiltration indicates tumor invasion burden of isocitrate dehydrogenase 1/2-wildtype gliomas

Few robust radiological markers have been identified for predicting the molecular status of gliomas. Recently, gyriform infiltration (GI) has been identified as an imaging biomarker for molecular glioblastoma (mGBM). This study aimed to validate the diagnostic value of GI in predicting the molecular status of diffuse gliomas. Clinical data were retrospectively collected from patients treated at a single center. Their imaging findings, including GI and the status of molecular markers, including IDH TERT were compared. This study enrolled 137 patients, 16 (12%) of whom, were diagnosed with GI. The vast majority of GI-positive cases were IDH-wildtype (15/16 cases), including four mGBM and six histologically diagnosed glioblastoma cases. The diagnostic sensitivity and specificity of GI in predicting mGBM were 24% and 90%, respectively, and its diagnostic sensitivity and specificity in predicting IDH-wildtype gliomas were 15% and 97%, respectively. GI was also observed in IDH-wildtype gliomas without the molecular and histological features of glioblastoma. All five GI-positive cases with available ¹¹C-methionine positron emission tomography scans showed increased tracer uptake in the GI area. GI is highly specific to IDH-wildtype gliomas. It delineates the tumor invasion burden and should be included as a target for local therapy, including radiation therapy.